1. Field of the Invention
The present invention generally relates to vehicle sound emitting technology for informing a person in an area surrounding of the vehicle that the vehicle is moving in an advancement direction, e.g., forward or rearward. More specifically, the present invention relates to a vehicle notification sound emitting apparatus that emits a notification sound to inform people of the existence of the vehicle.
2. Background Information
Some vehicles have a very quiet operating sound and/or moving sound (including a vehicle equipped with an internal combustion engine). For example, an electric powered vehicle such as an electric car configured to be electrically driven (EV drive) using only an electric motor is typically very quiet while operating and/or moving. Also for example, a hybrid vehicle having an electric drive mode (EV mode) in which the vehicle is driven solely with an electric motor is typically very quiet while operating and/or moving. In such very quiet vehicles, the operating sound and/or moving sound (vehicle information) such as the existence of the vehicle, an intent of a driver as indicated by a gear shift or other operation, an advancement direction of the vehicle (forward or reverse), a vehicle speed and/or other traveling condition of the vehicle are often not perceivable to a person in a surrounding area of the vehicle by emitting a notification sound to the outside of the vehicle. Thus, while typically it is desirable for the occupants of the vehicle to have a very vehicle, there are times when it is desirable for the vehicle convey the existence of the vehicle to a person in a surrounding area of the vehicle by emitting a notification sound to the outside of the vehicle.
Among the vehicle information mentioned above, technology has been proposed for emitting a movement notification sound to inform a person in an outside area surrounding a vehicle that the vehicle is moving in a forward direction or a reverse direction, (i.e., an advancement direction). For example, conventional movement notification sound technology is disclosed in Japanese Laid-Open Patent Publication No. 2005-343360. More specifically, this patent publication proposes a notification sound emitting apparatus that emits a notification when a vehicle starts into motion and starts advancing forward or in reverse and to vary a volume of the notification sound in accordance with a speed of the vehicle. With this conventional vehicle notification sound emitting apparatus, a notification can be provided which indicates the existence of the vehicle and the fact that the vehicle is moving.